The Clinical Trial Core has been established to provide support in the development and performance of the clinical trials in this proposal. This includes clinical resource support for the mesenchymal stem cell clinical program (Project 1,Specific Aims 2 and 3), and the cardiac stem cell clinical program (Project 3, Specific Aims 2 and 3). The aims are to provide: 1. Investigator support: This support includes assisting with protocol development, patient recruitment, assessing appropriateness for entry into the studies, obtaining informed consent, assisting with data collection and evaluation of the safety and efficacy of stem cell therapy, and assisting with clinical follow-up of the enrolled patients. Investigators in the Clinical Core will work closely with the investigators in each of these projects, as well as the Data and Coordinating Center, the Food and Drug Administration, and the National Heart Lung and Blood Institute to ensure appropriate conduct of the trials. 2. Nursing support: The critical role of the research nursing team includes assisting patient recruitment and enrollment, data entry, patient instruction, patient follow-up, patient safety evaluation, study coordination, and data entry. 3. Equipment: State of the art dedicated research equipment that will be utilized to measure efficacy in these trials includes a cardio-pulmonary exercise laboratory. Other state of the art equipment utilized in these clinical programs includes a catheterization laboratory dedicated to performing right heart catheterizations and endomyocardial biopsies, echocardiogram, ECG machine, and computers. Separate state of the art catheterization and electrophysiology laboratories are present to support the specific aims of this proposal. 4. Investigators and nurses in the Clinical Core will coordinate subject participation and evaluation with the General Clinical Research Center at the Johns Hopkins Hospital.